qt5base-lts/cmake/FindWrapRt.cmake

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# We can't create the same interface imported target multiple times, CMake will complain if we do
# that. This can happen if the find_package call is done in multiple different subdirectories.
if(TARGET WrapRt)
set(WrapRt_FOUND ON)
return()
endif()
include(CheckCXXSourceCompiles)
include(CMakePushCheckState)
find_library(LIBRT rt)
cmake_push_check_state()
if(LIBRT_FOUND)
list(APPEND CMAKE_REQUIRED_LIBRARIES "${LIBRT}")
endif()
check_cxx_source_compiles("
#include <unistd.h>
#include <time.h>
int main(int argc, char *argv[]) {
timespec ts; clock_gettime(CLOCK_REALTIME, &ts);
}" HAVE_GETTIME)
cmake_pop_check_state()
Write find_dependency() calls in Qt Module config files This change introduces a new function called qt_find_package() which can take an extra option called PROVIDED_TARGETS, which associates targets with the package that defines those targets. This is done by setting the INTERFACE_QT_PACKAGE_NAME and INTERFACE_QT_PACKAGE_VERSION properties on the imported targets. This information allows us to generate appropriate find_dependency() calls in a module's Config file for third party libraries. For example when an application links against QtCore, it should also link against zlib and atomic libraries. In order to do that, the library locations first have to be found by CMake. This is achieved by embedding find_dependency(ZLIB) and find_dependency(Atomic) in Qt5CoreDependencies.cmake which is included by Qt5CoreConfig.cmake. The latter is picked up when an application project contains find_package(Qt5Core), and thus all linking dependencies are resolved. The information 'which package provides which targets' is contained in the python json2cmake conversion script. The generated output of the script contains qt_find_package() calls that represent that information. The Qt5CoreDependencies.cmake file and which which dependencies it contains is generated at the QtPostProcess stop. Note that for non-static Qt builds, we only need to propagate public 3rd party libraries. For static builds, we need all third party libraries. In order for the INTERFACE_QT_PACKAGE_NAME property to be read in any scope, the targets on which the property is set, have to be GLOBAL. Also for applications and other modules to find all required third party libraries, we have to install all our custom Find modules, and make sure they define INTERFACE IMPORTED libraries, and not just IMPORTED libraries. Change-Id: I694d6e32d05b96d5e241df0156fc79d0029426aa Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>
2019-04-24 15:14:25 +00:00
add_library(WrapRt INTERFACE IMPORTED)
if (LIBRT_FOUND)
target_link_libraries(WrapRt INTERFACE "${LIBRT}")
endif()
set(WrapRt_FOUND "${HAVE_GETTIME}")